Civil Law

The recent report of H5N1 influenza in a pig in the US is getting a lot of attention. That’s warranted since it’s noteworthy, but as is typical, a lot of the social media buzz is overblown. This is a concerning situation that we need to watch, and we need to up our overall game with H5N1. However, this recent finding is neither unexpected nor a doomsday situation.

The highlights of the recent event:

• H5N1 flu was found in a pigs and poultry on a small backyard farm in Oregon.
• There were only 5 pigs on the farm. They were healthy but were tested as part of the response to infected poultry.
• The pigs were euthanized as part of the response. (From some standpoints that makes sense. However, it also means killing animals (probably pets) that would likely have survived and presumably could have been effective isolated and missing an opportunity to see what happens after exposure to better understand risks.
• Two tested negative. One was positive. Results are pending for 2.

The concerning bits…

• We simply don’t want flu transmitted to other animals. Every mammal that gets infected with avian creates more potential for the virus to adapt to mammals, potentially creating more risk to us (and other animal species)
• We really don’t want transmission of flu to species that have their own flu viruses and/or that are susceptible to human flu. Pigs cover both of those. We have a few circulating swine flu viruses and pigs can get human flu. We’re concerned about a pig having H5N1 and another flu virus, with subsequent recombination….mixing of those viruses to make a virus that might be more transmissible in humans but still far enough removed from our human flu strains that we don’t have pre-existing immunity from vaccination or previous infection. That’s how mew pandemic strains develop

The good bits…

• This is one of many, many spillovers into wild and domestic animals (well..that’s not really good news but it’s context.). A spillover into this pig is in some ways no different than the countless spillovers into other animals that didn’t get any press.
• This was a small backyard farm. With only 5 pigs, odds are exceptionally low that there was circulating swine flu on the farm.
• Pigs on this farm probably had outdoor access and there were infected poultry, so in some ways I’d be surprised if they didn’t get infected. How pigs are raised has many trade-offs. Outdoor access can be good for pig welfare but it adds various infectious disease risks.
• This was probably a dead end host situation..the pig(s) got infected from birds and this local H5N1incident died out. If the pigs didn’t infect someone or something else, they play no role in transmission or viral evolution.

My guess is that, despite all the doomsday prophesies on social media, this specific event will be a nothing-burger. It’s a spillover to a domestic animal that’s probably not anywhere unique as we know, since we probably miss the vast majority of these. At the same time, it’s a warning shot that if this virus stays poorly controlled, we have continual risk of it becoming something bad.

I’m not worried about the current H5N1 virus.

• It’s not a big deal.

I’m wary of what it could become, given the risk circumstances.

The problem is that it keeps getting opportunities to change. We can’t control H5N1 in wild birds. It’s going to be around for a while, if not permanently. We can do a much better job trying to control it in dairy cattle and we can be more proactive and ready to act (actually act…not talk about acting) should there be more spillovers into domestic animals.

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